Presentation on Engine Teardown training

25/12/2007 to 28/12/2007Vikrant S. Date

ContentsIntroductionMain Engine PartsDescription of Engine partsClassification Of Cummins EnginesEngine systemsTappet setting & Injector setting

Cummins Diesel Engines & GensetsDiesel Engines:Diesel engines are also known as Compression Ignition (CI) engines. In Cummins only heavy-duty four stroke engines are manufactured.CUMMINS GENERATOR SET:Hospitals, factories, theaters, and hotels have all benefited by installing Cummins genets before the onslaught of power shortages. Farsighted entrepreneurs are not only planning for immediate needs but are projecting future demands in planning for emergency power supplies.

CYLINDER BLOCK: CYLINDER HEADS: PISTONS AND PISTON RING:CONNECTING ROD:CRANKSHAFT:BEARINGS:FLYWHEEL:CAMSHAFT:LEVER:VALVES:OIL SUMP: BALANCER:VIBRATION DAMPER: GASKETS:THERMOSTAT:TURBOCHARGER:AFTER COOLER:Main Parts Of Diesel Engine Are:

Engine Which we Disassembled:NT455

CYLINDER BLOCK: This is the main framework of the engine and all the parts are mounted on it. It consist of linear bore, water heater, no. of oil passages & water passages & half crank bore, cam bore etc.The true end of the cylinder block are generally known as,gear endflywheel end.Four sides are (line engine),pan sideHead sideCam sideGen side MATERIAL.Plain gray cast iron,

CYLINDER HEAD: The cylinder head of a medium sized engine is made up of close-grained cast iron or nickel cast iron. . Large cylinder heads are made of low carbon steel or welding of steel plates or drop forged. The cylinder heads accommodates the valves and is exposed to combustion pressure. MATERIAL:-Gray Cast Iron (180 to 240 BHN). Mo, Cr, are used as a alloying element

CYLINDER HEAD:

PISTONS AND PISTON RING The piston is the reciprocating element, which is moved by the combustion pressure. The piston is made very close fit to the cylinder walls. Piston rings are fitted on the piston to make it gas tight. At the top of the piston are inserted several compression rings which, seal the space between the piston and the liner, thus preventing the high pressure combustion gases or the air charge from escaping down the liner during the compression stroke.

CONNECTING ROD - The connecting rod transforms the reciprocating motion of the piston into rotational motion of the crankshaft. It is free to oscillate on the gudgeon pin and this end is called small end, while the other end, which oscillates, is called big end. Bearings are attached at both ends. The rods are forged of high alloy steel.MaterialCr-Mo-Ni Steel

CRANKSHAFT: - The crankshaft rotates in the main bearing, which is set in the crankcase. The greater the number of bearing in the crankshaft more rigid is the set-up. Crankshafts are commonly forged either from open hearth or high strength alloy steels.MaterialAlloy Steel

BEARINGS: The term bearing is applied to machine parts, which transmit forces or loads from moving to the stationary parts and thus support the moving parts. The surface in contact under pressure is called bearing surfaces. Bearings are divided into two groups depending on the parts that they support. For rotary motion Journal bearings in which the load acts normal to the axis of rotation and Thrust bearing in which the main load acts along the normal to the axis of rotation. For reciprocating motion cylinder/ cylinder liner support the moving piston for rocking / oscillating motion. Piston pin bushing support the piston pin.

FLYWHEEL: The flywheel is fitted in order to smooth the cyclic fluctuations in the torque of flywheel is to store up the energy developed by the gases in the engine cylinder thereby keeping the crankshaft rotating at uniform speed.

CAMSHAFT: A cam is an eccentric projection on a revolving disc used for timing the opening and closing of the valves through various intermediate parts. Most diesel engines have cams forged or cast as one piece with the camshaft and then machined, usually ground to the required exact profile. The advantage of such an integral camshaft is that if one valve in the cylinder is timed correctly then all valves are timed correctly. Camshafts are made from forged steel usually of nickel chromium alloy steel, and the larger camshafts are often bored hollow. The cam follower is the engine part that is in contact with the cam and transmits the action of the cam to the push rod.

Turbo Charger:The turbocharger forces additional air into combustion chamber, so that engine can burn more fuel and develop more horsepower than if it were naturally aspirated. In some cases the turbocharger is used for the engine to retain efficiency (balanced fuel to air ratio) at altitudes above sea level.The turbocharger consists of a turbine wheel and a centrifugal blower, or compressor wheel, separately encased but mounted on and rotating with a common shaft.The power to drive the turbine wheel, which in turn drives the compressor, is obtained from energy of engine exhaust gases. Rotating speed of the turbine changes as the energy level of the gas changes; therefore, the engine is supplied with enough air to burn fuel for its load requirements. The turbocharger is lubricated and cooled by engine lubricating oil.

Turbo Charger:

Turbo Charger:

AFTER COOLER: After cooling is used on some Cummins turbocharged engines to achieve lower inlet air temperatures. Coolant is circulated through cooling elements located in the intake manifolds. It cools and condenses the air, which gets heated up in the turbocharger. An after cooler is fitted into the intake manifold. The incoming air passes around this element and its temperature drops, making it denser and thus more air is made available for combustion of fuel and thus increasing efficiency.

Turbo Charger & After cooler:

CLASSIFICATION OF CUMMINS ENGINES: Cummins engines are classified into series like: -N-Series: The cylinders have "in line" configuration. Numbers of cylinders are 4 or 6.K-Series: The cylinders have both "in line and "V" combination. The number of cylinders is 6, 12 or16.V-Series: The cylinders have "V" combination. Number of cylinders are 12. VTA is a type of engine in which 'V' stands for series of engine 'T' is turbo charged aspiration and 'A' stands for After cooler.

Engine systemsFuel SystemAir systemCooling systemLubrication system

Fuel system Fuel supply Fuel tank

Fuel filter

Fuel pump

Injector

Return from injector

Fuel SystemThe PT fuel system is used exclusively on Cummins Diesel Engines. PT is an abbreviation for "Pressure Timing". The operation of Cummins P.T Fuel system is based on the principle that the volume of liquid flow is proportional to the fuel pressure, the time allowed to flow and the passage size through which the liquid flows.

Fuel Flow Diagram:

PT Fuel PumpInjectorFuel FilterFuel tank

Fuel flow Diagram

Air systemAir Flow Turbo charger After cooler HousingAfter cooler coreIntake compressor tubesIntake manifoldIntake portIntake valves

Air System:The diesel engine requires hundreds of gallons of air for every gallon of fuel that it burns. For the engine to operate efficiently, it must breath freely. The intake air should always be routed through an air cleaner. The cleaner may be mounted on engine or equipment and may either be oil bath, paper element or composite type depending upon engine application. Air is routed from air cleaner directly to intake air manifold or turbocharger and/or after cooler

Air System

Cooling systemFlow of CoolantWater pumpBy pass tube/RadiatorCoolant in BlockCylinder linerCylinder HeadThermostatCoolant filter Oil coolerAfter cooler housingAfter cooler core

Cooling System: Water is circulated by a centrifugal water pump mounted either in or on the front of the engine belt driven from the accessory drive or crankshaft.Water circulates around wet type cylinder liners, through the cylinder heads and around injector sleeves. Injector sleeves, in which injectors are mounted, are designed for fast dissipation of heat. The engine has a thermostat or thermostats to control the engine operating temperature. A radiator and fan or heat exchanger cools engine coolant. In case of engine with after cooler, water is directed to the after cooler. Water flows forward through the after cooler to the water crossover to the thermostat housing.

Coolant Flow

Lubrication systemFlow of LubricantLube oil pumpLub oil filterDischarge tubeCylinder block gallery & turbo chargerPiston cooling nozzleCylinder Block & Cam shaftCylinder headOil coolerReturn to Oil sump

Lubrication SystemCummins engines are pressure lubricated i.e. pressure is supplied by a gear type lubricating oil pump located in oil pan or on the side of the engine.A pressure regulator is mounted in the lube oil pump to control lube oil pressure. Filters and screens are provided in lubricating oil system to remove foreign material from circulation and prevent damage to bearings or mating surfaces. A bypass valve is provided in full-flow oil filter as insurance against interruption of oil flow by a dirty or clogged element.

Lubrication System

Valve clearance Setting Fixture:

Injection timing setting fixture

Fuel injection cycle

Engines in learning centre

Engine teardown Training batch 25-28dec2007

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